Bull Canyon Agate is a beautiful translucent moss agate that comes from the Northern California/Nevada border area.
The moss is usually red in color, but can be green or brown and the long swirling stands make vivid patterns. This material is also known as a "tube agate". Tube agate forms when flow channels are captured in the structure of the growing silica. The "moss" then appears as long tubes in the stone.
Because of the hardness ( 7 on the Mohs scale) agates take a high polish and make great gemstone cabochons for jewelry.